The invention relates to a liner to be used as internal lining for vehicle roofs, self-supporting and made of several layers, all but one of them acting as liner support, the other as an outer decorative layer. The set of three layers is a sandwich with good stiffness properties to make it self-supporting.
The object of the invention is to provide a single block liner, that is, a single-component one, so that the layers which make up the self-supporting structure are joined to each other by pre-heating and the set of them is molded to the outer decorative layer, of a pleasant look and feel.
The internal lining of vehicle roofs generally requires use of a liner material which is self-supporting, adapts easily to the diverse shapes of different roofs, is lightweight and in addition provides a pleasant external feel and look, also requiring good sound absorption properties to improve inner comfort.
In order to fulfill these requirements, the use of multimaterial liners is generally resorted to, in which the different materials are arranged in thin layers glued to each other, so that each layer provides its characteristics to the resulting set or sandwich.
A common configuration used consists of a first layer, in contact with the roof, made of a liner material, to which is adhered a second layer consisting of a fiberglass grid or mesh, these layers being joined to each other by glue. Over the fiberglass grid or mesh is placed a substantially thicker central layer, on top of which is another fiberglass grid or mesh, glued to a final outer layer which is the accessible layer of the lining, this last layer made of a lightweight material.
These materials have certain drawbacks, mainly resulting from the use of a fiberglass mesh, with the well-known handling problems. Furthermore, since the layers are made of very different materials, recycling is difficult, and in addition there is the problem of using adhesives to join the different layers, all of this making the manufacturing process cumbersome.
The proposed liner, while maintaining the sandwich type structure described above, solves the aforementioned problems by having the xe2x80x9csupportxe2x80x9d block consist of three layers made of polyester fibers, keeping the final outer layer made of a lightweight material, so that these three polyester fiber layers perform the same function as the fiberglass and polyurethane foam layers normally used in manufacturing conventional self-supporting roof linings
The set of three polyester fiber layers is a sandwich with good stiffness properties, enabling the lining to be self-supporting and to comply with demands of vehicle manufacturers, in addition showing optimum acoustical properties.
Thus, the novelty of the invention lies in the composition of the three xe2x80x9csupportxe2x80x9d layers in the simple manufacturing process for the liner resulting from the use of these materials, since as they are polyester fibers the final product can be considered to be single-component, as the decorative layer is usually also made of polyester, having the advantage that the liner as a whole can be easily recycled, also eliminating the layers of adhesive required in traditional linings to join the different layers which make up the support structure.
The process for obtaining the liner is based on preheating the three xe2x80x9csupportxe2x80x9d layers, with a simultaneous molding of this support with the decorative layer, until the final shape of the liner is obtained.
The polyester fibers which make up the layers of the liner support structure, according to the invention, are of the type known as xe2x80x9cshortxe2x80x9d.
Regarding the polyester fiber layers in question, two of them are identical, composed of 100% short thermo-fusing polyester fibers with a low melting point, while the third layer, placed between the other two, is considerably thicker and, although it is also made of polyester fibers, has a different composition since thermofusing polyester fibers with a low melting point, solid fibers and hollow fibers can all be used, in different proportions and with different properties. This layer is made in the normal manner in manufacturing padding or fleece for filling clothing items or stuffing in the furniture industry, giving the final liner excellent sound absorption properties. These layers can have a greater or lesser grammage depending on the maximum final thickness required of the lining.